Water-soluble yellow monoazo pyrazolone dye



United States Patent Office Patented May 28, 1968 3,385,843 WATER-SOLUBLE YELLOW MONOAZO PYRAZOLONE DYE Hermann Remy, and Johann Wenghiifer, West Warwick, R.I., assiguors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Bruning, Frankfurt am Main,

Germany, a corporation of Germany No Drawing. Filed Dec. 3, 1965, Ser. No. 511,361 Claims priority, application Germany, Dec. 3, 1964,

1 Claim. or: 260-163) The present invention relates to a valuable, hitherto unknown monoazo-dyestuff and to a process for preparing it; more particularly, the present invention relates to a water-soluble yellow monoazo-dyestutf of the formula l SOsH no-cm-om-smQrrm in the form of its acid sulfuric acid ester and coupling in the usual manner with the pyrazolone of the formula S O3H or by subsequently converting into its acid sulfuric acid ester the dyestuif intermediate product which contains fl-hydroxyethyhsulfone groups 'and which has been prepared by coupling according to known methods the diazotized amine of the Formula 1 with the pyrazolone of the Formula 2. E-sterification of the coupling product obtained according to the second method can be carried out by treating it with amidosulfonic acid in the presence of appropriate organic solvents such, for example, as pyridine, at elevated temperature, or by treating the intermediate product with a sulfuric acid having a suitable concentration (90100% H 80 at room temperature.

The dyestufl obtained according to the process of the present invention dyes vegetal fibers in the presence of alkaline agents or wool from neutral or weakly acid baths brilliant greenish yellow shades that have very good properties of wet fastness.

The following examples illustrate the invention, but they are not intended to limit it thereto:

EXAMPLE 1 59.8 parts by weight of 1-(4'-sulfophenyl)-3-carboxypyrazolone-(5) were dissolved in 200 parts by volume of water having 20 C. and a pH of 6.5.

This solution was introduced into a diazo suspension of 56.2 parts by weight of the sulfuric acid semiester of 1-aminobenzene-4-fl-hydroxyethylsulfone, while keeping the temperature of the mixture below 15 C. by the addition of ice. The pH of the coupling solution was then increased to 6.4 by adding sodium carbonate and sodium bicarbonate and reduced to 5.8 after 2 hours by adding hydrochloric acid.

The ester dyestufi thus formed was salted out after some time by adding potassium chloride, the pH-value was reduced to 4.6 by means of hydrochloric acid and precipitation was completed by after-stirring for 24 hours. The product was then filtered with suction, washed with a 25% potassium chloride solution and dried.

The dyestuff thus prepared which corresponded to the formula was obtained in excellent purity and in a yield of 106 parts by weight, corresponding to 92% of the theory.

EXAMPLE 2 20.1 parts by weight of 1-amino'benzene-4-B-hydroxyethy-lsulfone were diazotized in the usual manner and coupled with 29.9 parts by weight of 1-(4'-sulfophenyl)- 3-car-boxy-pyrazolone-(5) at a pH ranging from 6.0 to 6.5. The coupling product was completely precipitated after some hours by adding potassium chloride and filtered with suction.

The dried dyestuff intermediate product thus obtained was introduced into 320 parts by volume of pyridine and the mixture was heated to C. 40 parts by weight of amidosulfonic acid were then added. Thereupon, the temperature rose quickly to about C. and was kept for half an hour at 100 to C. About 200 parts by volume of pyridine were then removed by distillation under reduced pressure and the residue was taken up in 400 parts by volume of water. The dyes-tuft was then salted out from its solution by adding potassium chloride and the pl-I-value of the reaction solution was reduced to 4.6. After having stirred for 24 hours, the dyestuif was filtered ofi, washed with a 25% potassium chloride solution and dried.

The dyestuif thus prepared, which was obtained in excellent purity and in a yield of 519 parts by weight, corresponding to 90% of the theory, was found to be identical with the product described in Example 1.

3 4 We claim: References Cited 1. The water-soluble yellow monoazo-dyestulf of the ma 3,234,207 2/1966 Berner et a1. 260-162 HOaSOCHz-CHr-SOr-N=Nfifi-COOH 5 FOREIGN PATENTS 973,569 10/1964 Great Britain.

CHARLES B. PARKER, Primary Examiner.

10 D. M. PAPUGA, Assistant Examiner.

SOaH 

1. THE WATER-SOLUBLE YELLOW MONOAZO-DYESTUFF OF THE FORMULA 